diff --git a/src/bin/embryo/embryo_cc_sc6.c b/src/bin/embryo/embryo_cc_sc6.c
index f8fc330939..b7cda645a0 100644
--- a/src/bin/embryo/embryo_cc_sc6.c
+++ b/src/bin/embryo/embryo_cc_sc6.c
@@ -72,7 +72,7 @@ hex2long(char *s, char **n)
      }				/* if */
 
    assert((*s >= '0' && *s <= '9') || (*s >= 'a' && *s <= 'f')
-	  || (*s >= 'a' && *s <= 'f'));
+	  || (*s >= 'A' && *s <= 'F'));
    for (;;)
      {
 	if (*s >= '0' && *s <= '9')